Enhanced balloon dilatation system

ABSTRACT

A balloon dilatation system is comprised of an elongated flexible advancement member which terminates in a tubular tracking member slidable over a guidewire. An inflatable balloon has proximal and distal ends, the proximal end communicating with an inflation channel, and the distal end attaching to the tracking member. The balloon portion is coextensive with but not attached to the advancement member.

This application is based upon co-pending U.S. provisional patentapplication Ser. No. 60/085,636, filed May 15, 1998.

SCOPE OF THE INVENTION

This invention relates to the field of balloon dilatation. Moreparticularly, this invention relates to improved balloon dilatationsystems wherein dilatation balloons are attached to the distal end ofadvancement means.

BACKGROUND OF THE INVENTION

Balloon dilatation catheters have been used to dilate various types ofstrictures in blood vessels and other body lumens for over twenty years.Typically, such catheters comprise a balloon mounted on the distal endof an elongated flexible shaft and an inflation tube or lumen extendinglongitudinally within the shaft from its proximal end to the interior ofthe balloon. Among the major advancements in balloon dilatationcatheters has been the development of smaller catheters that can be usedin smaller and/or more distal anatomical locations, and the developmentof catheters that can be rapidly exchanged. Examples of such cathetersare described in U.S. Pat. No. 4,748,982 (Horzewski), U.S. Pat. No.4,762,129 (Bonzel), U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No.5,061,273 (Yock), U.S. Pat. No. 5,569,199 (Solar) and U.S. Pat. No.5,728,067 (Enger). Because these catheters have become moresophisticated and complex in design, and despite the manufacturers'experience in manufacturing them, these catheters are expensive to make.Furthermore, despite these improvements, difficulties are stillencountered in advancing catheters through tortuous anatomy and safelycrossing very tight strictures and stenoses in the vascular system andother body lumens or cavities.

Recently vascular stents have been shown to play an important role inreducing the restenosis rates associated with balloon angioplasty.However, stents are sometimes lost from the delivery systems and aredifficullt to retrieve safely. In addition, stents cannot completelyovercome the trauma and injury that result from balloon dilatation.Thus, there is a need for an enhanced balloon dilatation catheter.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an enhanced dilatationsystem that is extremely low-profile to more easily and safely crossvery tight strictures and stenoses in the vascular system and other bodylumens or cavities.

It is also an object of the invention to provide an enhanced dilatationsystem that provides for an improved means for crossing tight stenoses,as well as to navigate tortuous anatomy.

It is another object of the invention to provide an enhanced dilatationsystem, that has the ability to be exchanged rapidly.

It is yet another object of the invention to provide an enhanceddilatation system that can be used to retrieve dislodged stents.

It is a further object of the invention to provide an enhanceddilatation system that can be manufactured inexpensively and morereliably then currently available stents.

It is a yet further object of the invention to provide an enhanceddilatation system that has means to dilate stenoses while causing lesstrauma to the patient.

It is also an object of the invention to provide an enhanced dilatationsystem allows placement of an additional catheter or instrumentalityadjacent to said dilatation catheter.

These and other objects of the invention will become more apparent fromthe discussion below.

SUMMARY OF THE INVENTION

According to the invention, an enhanced balloon dilatation systemcomprises an elongated advancement member which terminates in a tubulartracking member, and an inflatable dilatation balloon having proximaland distal ends. The proximal end of the dilatation balloon is in fluidcommunication with an inflation channel, and the distal end of thedilatation balloon is attached to the tubular tracking member. Duringadvancement of the catheter, the dilatation balloon and inflationchannel are somewhat coextensive with, but unattached to, theadvancement member. The tubular tracking member is slidable over aguidewire.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the invention will beapparent upon consideration of the following detailed description, takenin conjunction with the accompanying drawings, in which the referencecharacters refer to like parts throughout and in which:

FIGS. 1 to 3 are each a schematic, lateral view of an embodiment of theinvention;

FIG. 4 is an enlarged illustration of the distal portion of anadditional embodiment of the invention;

FIG. 5 is an enlarged illustration of the proximal portion of analternate embodiment of the invention;

FIG. 6 is a cross-sectional view of a clamping member used in the FIG. 5embodiment; and

FIGS. 7 and 8 are each a schematic, lateral view of an additionalembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 3, the enhanced balloon dilatation system,designated generally as 1, has an elongated advancement member 5.Preferably advancement member 5 is formed of a flexible wire or,alternately, of spring hollow hypotubing. Advancement member 5preferably has a diameter of from about 0.008″ to 0.035″, which diametercould be larger or smaller depending on the application. Advancementmember 5 has sufficient column strength and flexibility to provide foradvancement of the catheter through tortuous anatomy. Preferably,advancement member 5 is rigid at its proximal end and becomesincreasingly more flexible as it extends distally. This may beaccomplished by a number of ways known in the art, including, but notlimited to, tapering, selective heat treatment and/or formingadvancement member 5 from a composite of materials with variousproperties.

Advancement member 5 terminates at its distal end 6 in an elongatedtubular tracking member 7. Tracking member 7 has a tubular configurationand is adapted to slide over a standard guidewire 9 to allow system 1 toadvance easily to a desired location within a patient's body. Trackingmember 7 has an open proximal end 11 and an open distal end 8, and ispreferably formed of a flexible polymeric tube, a spring coil, or acombination thereof. Tracking member 7 is preferably about 10 to 50 cmlong and has an inner diameter that is sized to accommodate guidewire 9,most preferably approximately from about 0.012″ to 0.040″. Optionallytracking member 7 has an inner, outer, or inner and outer coating with alubricious material to aid in its movement over the guidewire.Lubricious materials for this purpose are well-known in the art.

Advancement member 5 and tracking member 7 are attached by any suitablemeans known in the art, such as by fusion or a non-toxic adhesive.Alternatively, advancement member 5 and tracking member 7 may beintegrally formed during manufacture.

System 1 also has an inflatable balloon 10 having a proximal end 12 anddistal end 14. Distal end 14 of balloon 10 is attached to trackingmember 7 by any suitable means known in the art, such as by fusion,adhesive bonding or integral formation, and moves therewith. Distal end14 of balloon 10 may be attached to distal end 8 of tracking member 7,as shown in FIG. 1, or preferably, distal end 14 of balloon 10 isattached to the proximal end 11 of tracking member 7, as shown in FIG.3. Balloon 10 is formed of a very thin-walled, preferably less than0.001″ thick, polymeric material. Balloon 10 may be formed of any one ofa variety of suitable materials known in the art.

Proximal end 12 of balloon 10 communicates with an elongated inflationchannel 15 that extends proximally through a corporeal lumen. Inflationmeans 15 is formed preferably of a polymeric tubular film that willallow inflation channel 15 to collapse to a smaller profile when notbeing used for inflation of balloon 10. The wall thickness of inflationchannel 15 should preferably be less than 0.001″. When inflated,inflation channel 15 will have a diameter of approximately 0.010″ ormore, depending on the application. Alternatively, inflation channel 15may be fabricated out of a non-collapsible tubing material as would befamiliar to one skilled in this art. As shown in FIG. 3, inflationchannel 15 may have position markers 13 on its proximal portion.Position markers 13, which may be applied by ink or other suitable meansknown in the art, correspond to similar markers on advancement member 5.Such markers provide visual confirmation of concurrent movement ofinflation channel 15 and advancement member 5 during advancement andwithdrawal of system 1.

Inflation channel 15 has a hub 16 at its opposite, proximal end. Hub 16is a standard LUER® lock connector that allows connection of inflationmeans 15 to standard balloon inflator devices or syringes (not shown).By this means, balloon 10 is in fluid communication with an inflator.

As noted above, distal end 14 of inflatable balloon 10 is attached totubular tracking member 7. In this way, as tubular tracking member 7travels through the body along the path of guidewire 9, inflatableballoon 10 is pulled along with tracking member 7 to the desired site.However, although balloon 10 lies coextensively with advancement member5 (FIGS. 2 and 3) and/or tracking member 7 (FIG. 1), it is unattached toadvancement member 5. In this most preferred embodiment of leastattachment, pushing on advancement member 5 causes balloon 10 to beeasily pulled through the anatomy and tight strictures and stenoses.Since the balloon is not being pushed through a stenosis, there is notendency for the balloon to compress longitudinally and increase inprofile and bulk. Such an occurance, which may be found in prior artcatheters where the balloon is attached proximally and distally to thecatheter shaft, can impede advancement and crossing, as well as resultin vascular trauma and clinical complications. Since there is no bulkycatheter structure within the interior of the balloon (as is found inprior art catheters), the very thin balloon material can easily fold andconform as required to cross a stenosis with minimal friction and traumaas it is pulled across by the tracking member.

As shown in FIG. 3 a wire 2 can optionally extend at least partiallywithin the inflation channel 15 to the distal end 14 of balloon 10. Wire2 may provide support to the inflation channel 15 and balloon 10 whichmay be required in some applications. The support wire may bepermanently mounted, or alternatively, it may be removable and used asneeded. Also, as shown in FIG. 3, the dilatation system may haveradiopaque markers 17 to allow the system's position to be monitored,and the proximal ends of the advancement member 5 and/or inflationchannel 15 may have one or more visual markers 13 to indicate thelengths inserted. The radiopaque markers may be comprised ofconventional radiopaque materials such as gold or platinum, and thevisual markers may be comprised of physiological acceptable inks orcoatings, preferably in bright or fluorescent colors.

To summarize use of the preferred embodiment of the present invention,guidewire 9 is first laid in place within a corporeal lumen through anyof the means well-known in the art. With use of advancement member 5,tracking member 7 is advanced into the corporeal lumen over guidewire 9.As tracking member 7 is advanced into the corporeal lumen, inflatabledilatation balloon 10 is pulled along with it by virtue of theattachment of distal end 14 of dilatation balloon 10 to either proximalend 11 or distal end 8 of tracking member 7. Once dilatation balloon 10is in a desired position within the corporeal lumen, dilatation balloon10 is inflated via inflation means 15 and hub 16.

It is contemplated that tracking member 7 can be varied to providealternative embodiments of the catheter system 1 of the invention. Forexample, the length of tracking member 7 may either be made longer orshorter. In the embodiment of the invention shown in FIG. 2, thetracking means has been shortened to a loop 18. Alternatively, it iscontemplated that tracking member 7 may extend as an elongated tubularmember the full length of system 1, from a proximal position outside thebody lumen all the way to distal end 8, to allow fluid administration ofthe treatment site. Also, the distal end of advancement member 5 couldextend distally of tracking member 7. Moreover, in one embodiment of theinvention dilatation balloon 10 may be detachable.

In addition, it is contemplated that tracking means 7 may besingle-lumen, so that it accommodates only guidewire 9, or it may bemulti-lumen, so that it can perform other functions as well. Forexample, the multi-lumen tracking member 19 shown in FIG. 4 containslumen 3 for advancing over guidewire 9 and lumen 20, which provides aconvenient means for attachment to advancement member 5. Advancementmember 5 may be hollow to provide an alternative means for fluidadministration to the treatment site. Lumen 20 may be open at the distalend 4 of tracking member 19, and tracking member 19 may alternativelyhave side holes 21 which provide communication from lumen 20 to theexterior of tracking member 19. Tracking member 19 may also be enlargedand/or lengthened to facilitate perfusion during balloon inflation.

It is further contemplated that, in some applications, it may be deemeddesirable to provide one or more additional attachment points betweenthe inflation channel and the advancement member at various locationsalong the advancement member's length. A preferred method of attachmentemploys a removable clamping member 22 as shown in FIGS. 5 and 6.Clamping member 22 holds inflation channel 15 stationary with respect toadvancement member 5 during withdrawal of dilatation system 1. Clampingmember 22 is preferably removed or loosened during dilatation systemadvancement to optimize the pulling forces on the balloon. It iscontemplated that in some instances more than one clamp 22 might beused.

Further, it is envisioned that the balloon and the inflation channel maybe formed from the same material or they may be formed independently andsubsequently attached by suitable known means. In addition, the distalextension of the balloon may be molded or otherwise formed to the shapeof the tracking member.

In yet another alternative preferred embodiment of the invention, theadvancement member and the tracking member may be formed in multiplesegments each having varying mechanical properties which will allow forthe customization of the catheter to a particular need.

The embodiment of the invention shown in FIG. 7 has a dilatation balloon22 and a flexible, torqueable, advancement member 23. The distal portion24 of dilatation balloon 22 is fixedly attached to the distal end 25 ofadvancement member 23. Advancement member distal end 25 may optionallyhave a flexible spring tip 26.

The proximal portion 27 of dilatation balloon 22 is in fluidcommunication with an inflation channel or means 28 having a hub 29 forconnection to an inflation source (not shown). Inflation channel 28preferably is attached to or wound about advancement member 23 in spiralfashion, in such a way to lower the profile of the system but to notinterfere with the fluid communication.

A torquer or rotator member 30 may optionally grip the proximal portionof advancement member 23 and inflation channel 28, to allow radialpositioning of advancement member 23. In this embodiment it is preferredthat the inflation means spirally wrap around the advancement member.Turning the proximal end of the advancement member with torquer 30 willallow distal end 25 of the advancement member 23 to be positioned at adesired radial location relative to dilatation balloon 22 within acorporeal lumen. A torquer 30 could also be used with the embodimentsshown in FIGS. 1 and 2, where the tracking means and advancement meanswould be radially positioned.

The dilation system of the present invention provides the user with anumber of significant advantages not otherwise obtainable with currentlyavailable catheters. For example, they are less bulky than otheravailable dilatation catheters and thus the balloon is able to moveagainst resistance more easily, which allows less traumatic crossing ofrestrictions. Also, pushing on the advancement member has the effect ofpulling the balloon along through the stenosis, and avoids the problemof bunching or gathering which occurs with other catheters. With a thinfilm balloon and inflation channel there is no dead space or volume thatneeds to be evacuated prior to use; therefore, little or no preparationis required. The smaller profile of the dilatation system of theinvention allows the dilatation balloon to be passed through stentseasily. Partial inflation of the dilatation balloon can grab apreviously inserted stent and facilitate retrieval of the stent. Thesmaller profile also permits passage through displaced stent struts.

Separating the dilatation balloon from a catheter shaft allows greaterdesign flexibility to allow one to provide dilatation systems withimproved handling characteristics, and the fewer bonds between theballoon and the advancement shaft results in greater reliability. Thesimplicity of construction of the system of the present inventionresults in lower manufacturing costs. For example, fewer bondingoperations are required, and expensive balloon folding processes can beavoided. Inflating the balloon against the advancement member ortracking member provides a focused force to enable the user to crackhard lesions at low pressure before the balloon is fully inflated. Doingso would allow vessel stretching to occur at a lower strain rate, whichwould minimize the trauma associated with balloon dilatation. With theguidewire 9 in place, the balloon can be inflated additionally againstthe guidewire, thus providing an additional area of focused force.

A further advantage of the present invention is that the design allowsadditional catheters or devices to be placed adjacent to the dilatationballoon, and to be exchanged without first removing the dilatationsystem. In this application, the advancement member also acts as anadditional guidewire. For example, while balloon catheter 1 is in placewithin a vascular lesion, a second dilatation system or catheter may beadvanced over the advancement member and its balloon positioned alongside the first balloon (to increase the effective diameter of thedilatation) or adjacent to the first balloon (to increase the effectivelength of the dilatation). An imaging catheter such as an intravascularultrasound catheter may be placed next to the first balloon to accessthe progress of the treatment without removing the balloon. A drugdelivery catheter may be utilized in this manner, and the balloon ofsystem 1 may be inflated at low pressure to provide vascular occlusionto improve the efficacy of the drug delivery. Likewise, various othercatheters and devices may be suitably employed.

Although the discussion above has been concerned with balloon dilatationsystems and/or catheters, other types of catheters or systems may embodythe present invention as schematically illustrated in FIG. 8. In FIG. 8,advancement member 5 terminates in a tubular tracking member 7, whichtracks over guidewire 9. Distal end 32 of instrumentality 31 is attachedto tracking member 7. Proximal end 33 of instrumentality 31 isunattached to either advancement member 5 or tracking member 7.Instrumentality 31 may be a laser, infusion tube, suction device,atherectomy means, or other therapeutic or diagnostic apparatus. Asrequired, a connecting member 34 may be attached to instrumentality 31.Connecting member 34 may be an electrical conducting wire, opticalfiber, tube, or the like.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained, andsince certain changes may be made in the constructions set forth withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention, which, as amatter of language, might be said to fall therebetween.

What is claimed is:
 1. A balloon dilation system comprising: a flexibleelongated advancement member having a proximal end and a distal end, atracking member having a proximal end and a distal end, said trackingmember being adapted to slide over a guidewire and being fixedlyattached to the distal end of the advancement member, an inflationchannel, and an inflatable dilation balloon having a proximal end and adistal end, the proximal end of the balloon being in fluid communicationwith the inflation channel, wherein only the distal end of the balloonis attached to the tracking member and wherein the advancement member isexternal to the balloon.
 2. The dilatation system of claim 1, whereinthe tracking member comprises two or more lumens.
 3. The dilatationsystem of claim 1, wherein the dilatation balloon is attached to thedistal end of the tracking member.
 4. The dilatation system of claim 1,wherein the dilatation balloon is attached to the proximal end of thetracking member.
 5. The dilatation system of claim 1, wherein thetracking member has a lubricious coating.
 6. The dilatation system ofclaim 1, wherein the tracking member is formed integral with thedilatation balloon.
 7. A balloon dilatation system comprising: aflexible elongated advancement member having a proximal end and a distalend, a dilatation balloon having a proximal end and a distal end, and aninflation channel, the proximal end of the balloon being in fluidcommunication with the inflation channel, wherein only the distal end ofthe balloon is attached to the distal end of the advancement member andwherein the advancement member is external to the balloon.
 8. Thedilatation system of claim 1 or 7, wherein the inflation channel issubstantially coextensive with the advancement member.
 9. The dilatationsystem of claim 1 or 7, wherein the inflation channel is in a spiralconfiguration around the advancement member.
 10. The dilatation systemof claim 1 or 7, wherein the advancement member comprises a flexiblewire or hypotubing.
 11. The dilatation system of claim 1 or 7, whereinthe advancement member is rigid at its proximal end and the advancementmember is increasingly more flexible as the advancement member extendsdistally.
 12. The dilatation system of claim 1 or 7, wherein theinflation channel is collapsible or noncollapsible.
 13. The dilatationsystem of claim 1 or 7, wherein the dilatation balloon or the inflationchannel, or both, have a wire reinforcement.
 14. The dilatation systemof claim 1 or 7, wherein the dilatation balloon and the inflationchannel are formed integral.
 15. The dilatation system of claim 1 or 7,wherein the inflation channel is attached to the advancement member atat least one point.
 16. The dilatation system of claim 1 or 7, whichalso comprises a torquer attached to the proximal end of the advancementmember.
 17. The dilatation system of claim 1 or 7, wherein the balloonand the inflation channel are unattached to the advancement member. 18.The dilatation system of claim 1 or 7, wherein the balloon and/or theinflation channel are attached to the advancement member.
 19. A methodof positioning the distal end of a balloon dilatation catheter at adesired location within a patient's body, which comprises the step of:advancing a dilatation system of claim 1 or 7 through a corporeal lumenso that the distal end of said balloon dilatation catheter is positionedat a desired location.
 20. The method of claim 19, wherein anotherdilatation system or other medical device is advanced distally over thedilatation system of claim 1 or
 7. 21. A medical delivery systemcomprising: a flexible elongated advancement member having a proximalend and a distal end, a tracking member having a proximal end and adistal end, said tracking member being adapted to slide over a guidewireand being fixedly attached to the distal end of the advancement member,and a medical instrument or device or a portion thereof having aproximal end and a distal end, the proximal end of the instrument ordevice being in communication with a source, wherein only the distal endof the medical instrument or device is attached to the tracking memberor the advancement member and wherein the advancement member is externalto the medical instrument or device or a portion thereof.
 22. A balloondilation system comprising: a flexible elongated advancement memberhaving a proximal end and a distal end, a tracking member comprising twoor more lumens and having a proximal end and a distal end, said trackingmember being adapted to slide over a guidewire and being fixedlyattached to the distal end of the advancement member, an inflationchannel, and an inflatable dilatation balloon having a proximal end anda distal end, the proximal end of the balloon being in fluidcommunication with the inflation channel, wherein only the distal end ofthe balloon is attached to the tracking member and wherein theadvancement member is external to the balloon.
 23. A balloon dilatationsystem comprising: a flexible elongated advancement member having aproximal end and a distal end, a tracking member having a proximal endand a distal end, said tracking member having a lubricious coating,being adapted to slide over a guidewire, and being fixedly attached tothe distal end of the advancement member, an inflation channel, and aninflatable dilatation balloon having a proximal end and a distal end,the proximal end of the balloon being in fluid communication with theinflation channel, wherein only the distal end of the balloon isattached to the tracking member and wherein the advancement member isexternal to the balloon.